Fluid filter



V- 1953 G. w. MORK ET AL FLUID FILTER Filed Aug. 2, 1948 62-05,:- W Amer;

IN V EN TORS,

Patented Nov. 24, 1953 2,660,312 .FLUID FILTER George W. Mork, South Milwaukee, and John E. Marson and Thomas G. Paulsen, Milwaukee,

Wis.,

assignors to Bucyrus-Erie Company,

South Milwaukee, Wis., a corporation of Delaware Application August 2, 1948, Serial No. 42,114

3 Claims.

Our invention relates to new and useful improvements in filters for fiuid circulating systems, more particularly to filters used to purify oil in hydraulic systems for the control of tractor equipment.

In such systems the presence of even a very small amount of dirt or abrasive foreign matter can cause damage to and adversely affect the operation of the hydraulic controls. Hence rapid and efficient filtering of foreign solids from the circulating system is imperative. Furthermore this filtering must be accomplished without appreciably retarding fiow upon which operation of the equipment depends, and it must be possible to remove the solids from the filter and/or replace the filter quickly and conveniently in the field without disassembling the main hydraulic circuit.

Accordingly the principal object of our invention is to provide a hlghly-eflicient quick-acting filter for a fluid circulating system.

A further object of our invention is to provide a filter that does not appreciably impede normal flow of fluid in the circulating system in which it is placed.

A further object of our invention is to provide a filter that is simple, inexpensive, compact and easily removable from the circulating system in which it is placed.

In addition to the objects above stated, we have worked out a number of novel and useful details, which will be readily evident as the description progresses.

Our invention consists in the novel parts, and in the combination and arrangement thereof, which are defined in the appended claims, and of which two embodiments are exemplified in the accompanying drawings, which are hereinafter particularly described and explained.

Throughout the description, the same reference number is applied to the same member'or to similar members.

Referring now to the accompanying drawings, it will be seen that:

Figure 1 is a view, partly in section, of the first embodiment of our invention, showing our filter element inserted in the elbow of an hydraulic circulating system.

Figure 2 is a sectional view taken along the line 2--2 of Figures 1 and 4.

Figure 3 is a view in parallel perspective of the filter element shown removed from the fluid conduit.

Figure 4 is a view, partly in section, of a second embodiment of our invention, showing the filter element inserted in a straight section of pipe of an hydraulic circulating system.

Referring now to Figures 1 to 3, we see that H and [2 represent the inlet and outlet respectively of a fiuid conduit l3 in an hydraulic circulating system. This conduit may be located at the exit port of a pump l4 (fragment only shown in the drawing), although this is not essential. Conduit 13 includes, adjacent its en trance H, an elbow l5 which is shown as a degree elbow, although this particular angle is not critical for our purpose. The outer wall [6 of conduit I3 is provided with an opening I! adjacent the exit l8 of elbow I5. Filter element I9 is mounted on base plate 20 which is adapted to be bolted to the outer wall l6 by bolts 2 l. The filter element is inserted through opening I1 and extends across the outer half of the conduit at the exit l8 of the elbow IS. The other half of the conduit constitutes an unobstructed passage 22 for the fluid. Filter element I9 is in the form of a pocket which comprises longitudinal walls 23, transverse Walls 24 and 25. Transverse wall 24 is inclined, in the direction of fiow, toward the outer wall [6 of the conduit, and is, with transverse wall 25,- perforated in the form of a filter screen.

By placing filter element l9 across only part of the conduit, leaving passage 22 unobstructed, it is possible to avoid impeding the flow of fluid when the filter screen becomes clogged with foreign particles. By placing the filter just at the elbow exit and adjacent the outer wall of the conduit, it is possible to collect in the filter practically all foreign particles in the fluid, such as fine pieces of metal, since these particles are thrown outwardly by centrifugal force as they pass through the elbow and enter the mouth 26 of the filter, leaving relatively pure the fluid that passes through passage 22.

Turning now, to Figure 4, it is seen that, in the second embodiment of our invention, the elbow used in our first embodiment is not employed, and the filter element I9 is inserted in a straight section of fluid conduit or pipe I3 having inlet II and outlet I2. In this embodi ment, normal flow of the fiuid through the conduit is not impeded appreciably by the filter element since such flow is Well within the capacity of unobstructed passage 22'. That portion of the fiow in the lower portion of the conduit inlet that is beyond the capacity of the filter to transmit, is deviated around the filter element, and thence through the passage 22'. The velocity of flow through passage 22' is accordingly considerably greater than the velocity of flow through the main portion l of the conduit. Foreign particles (indicated by broken arrows in Figure 4), being heavier than the fluid, does not, however, follow the stream lines indicated by full arrows in Figure 4) through passage, 22', but tend to pass straighten into the filter and are trapped on the as well as deviation around filter I 9 into. passage 22; whereas in the second embodiment.(Figure 2) the same result is achieved with somewhat'less filtering efiiciency by using the centrifugal effect due only to deviation of'fiow around the filter l9 into'passage 22. g

? Having 'nowdescribed twoembodiments of our-invention, we wish it to be understood that our irive'ntion is not to be limited to the specific form' or arrangement of parts herein described anaehown,

' Thus, it is evident that the particular form of the filter element'shown in the drawings is-mere- 1y; illustrativeof one possible embodiment, many suitable variations being feasible, for example. in number, location, extent, shape, and typed screening and trapping elements in the filter.

Furthermore, although'the invention has been described in its applicationtoa high-velocity oil circulating system commonly" used to actuate tractor-equipment, it is to be understood that the same'isequally-applicable to other liquid and fluid circulating systems. 4

In' -thecIaims, by inner wallof the conduit, we mean the side-of the conduit that is adjacent -the-point about'which the conduit is bent at the elbow, and by outer wall of the conduit we intend to refer to the side furthest fron'fthat point? We claim:

1. In a filter assembly for a fluid circulating system} thecombination of afluid conduit angled to form an' elbow; an unobstructed main passageway within said conduit adjacent the inher wall of the conduit at the exit of the elbow; and a filter located wholly within the conduit and extending inwardly from said outer wall of the conduit across onlythe part of the conduit that is adjacent the outer wall of the conduit adjacent the exit of the elbow; whereby foreign particles centrifuged in passing through said elbow will 'pass'into' and be retained by said filter withoutappreciably impeding normal flow offiuid through said main passageway.

2.-"A filter assembly according toclaim 1, fur- 6 ther characterized by the fact that the filter is adapted itol be inserted into and removed from 0 Number 4 the conduit through a hole in the wall of the conduit, and has attached thereto a base plate for sealing the hole in the conduit when the filter has been inserted therethrough into the conduit, and that said filter comprises a pocket element attached'to the inner face of the'base plate, the inner face of the base plate forming the outer side of the pocket, and said pocket element including a screen element extending from one end of the pocket adjacent one end of the inner face of the base plate inwardly at an oblique angle to the base plate-to form the inner side of the pocket, an inner'lip at the other end of the pocket, and an outer. lip adjacent the other end of the inner face of the base plate; said inner and outer lips defining the opening of the pocket so that said openingis. in'a plane perpendicular to the innerface. of the base plate and the axis of the conduit.

3. A removable filter element for insertion into a conduit through a hole in the wall of the conduit, said filter element'comprising: a base plate for sealing the hole in the conduit when the element has been inserted therethrough into the conduit, and a pocket element attached to the inner faced the base plate; the inner face of the base plate forming the outer side of the pocket, and said pocket element including a screen element extending from one end of the pocket adjacent one 'end of the inner face of the base plate inwardly at an oblique angle to the base plate to form the'inner side of the pocket, an inner lip at'th'e other end of the pocket, and an outer lip adjacent the other end of theinner 'face of the base plategsaid inner and outer lipsdefining the opening'of .the pocket so thatsaid'opening is in a planeperpendicular to the inner face of the base plate and the axis of the conduit.

GEORGE W. MORK.

JOHNE. MARSON.

THOMAS G. PAULSEN.

References: Gitedin the file-of this patent UNITED STATES PATENTS Number Bush Feb. 27, 1940 2,557,064

Alexander June-19, 1951 FOREIGN PATENTS Country Date Switzerland Feb. 28, 1934 France of 1942 Mosley June 23, 1936 

